hi parmeswari , always try to give variety of food to your baby, it will help her to develop taste for everything. if you wish to give her idli, try to make idli more healthy and enjoyable by your baby. you can try recipes mention below...
add boiled pureed palak to idli batter, idli will be of green in color.
add beatroot juice to idli batter to get pink color idli.
add boiled yellow moong daal to idli batter.
hope your baby enjoy these recipes.

Hi there's nothing to worry as eating anything new n then pooping is not bad. It's a sign that ur baby is digesting what ever u gv to her. Babies stomach is soft n sometimes don't digest things easily sometimes they vomit, sometimes they poop it's ok nothing to worry. Just b sure the motion should b normal not loose not tight.